Hello Mick,
I'm using the SX-900, but probably the same options on the Genos --- you can either choose to mirror the screen, or choose to display the Lyrics/Text screen only.
Go to your Menu, and "Utility" to see the options you can choose on Genos.
If you're using a USB to HDMI adapter, it will occupy the entire screen, and perhaps that's exactly what you want.
However, I've added a second adapter with the first one, the Andycine HDMI to USB video adapter, which can then be displayed as a resizeable window on your PC.
It essentially makes the keyboard appear as a "USB Camera" to Windows, which can be viewed by launching the "Camera" app on Windows.
I didn't even realize this could be done, but months ago, someone mentioned it on this forum, and it's ideal for me. Using Win 10 with dual 43" TV's for monitors.
Jerry